Black plug.

[scootsmith]

Can't seem to sort out running and plug tip is always black instead of nice brown colour. What can i do?? Running with new 100 top end on old v90. Leo vinci snail pipe with upjet..can't remember what size. Standard 16 carb but i don't know what standard setting are? B7HS plug. Anyone help?? She starts an runs ok but want her to have a nice healthy plug colour.

[willspeed]

take the jet out and the number should be stamped on the side, down jet then do a plug chop.

[jonnysnatchsniffer]

standard main jet on the v90 and 16/16 carb is 63 but the 100 uses a 19/19 with a 74 main so i reckon you probably wont need much more than a 66-70 main, are you runnig the filter if so take that off see if its any better